American Society for Bone and Mineral Research, Sept. 11-15, 2009

The American Society for Bone and Mineral Research 31st Annual Meeting took place Sept. 11 to 15 in Denver and attracted about 5,000 attendees from around the world, including Japan, France, Canada, Germany, and the United Kingdom. The meeting featured lectures, symposia, 1,500 poster presentations, and 300 oral presentations addressing new research, technology, and clinical treatments for bone diseases and disorders of mineral metabolism.

Osteoporosis was a dominant theme of the meeting. "Approximately one-third of the presentations covered topics that include population studies and animal models related to sex steroid effects on the skeleton, genetics, lifestyles, vitamin D and calcium intake, PTH hormone and inhibition of bone resorption by the bisphosphonates and the newest of targets for RANKL, the activator of osteoclastic bone resorption," said the society's president, Jane Lian, Ph.D., of the University of Massachusetts Medical School in Worcester.

Highlights included a series of Amgen-supported studies demonstrating the efficacy of denosumab, an antibody that blocks RANKL activity. "Being able to generate a safe antibody that blocks RANKL is an exciting development," Lian said. "The presented data was very promising."

In a post-hoc exploratory analysis of an ongoing, multicenter, Phase 2 study, researchers showed that twice-yearly subcutaneous treatment with denosumab for up to two years was associated with improved bone mineral density and parameters of hip structural analysis (HSA), a technique that estimates geometric properties of bone strength. They found that denosumab-treated patients experienced a 6.69 increase in the HAS measure of cortical thickness at the femoral shaft while placebo-treated patients experienced a 0.31 percent decrease.

These results extended previous findings that denosumab has beneficial effects on cortical bone, the dense outer shell of the skeleton that comprises approximately three-quarters of the total skeletal mass, and significantly increased bone mineral density at the lumbar spine, total hip, and femoral neck (7.4, 5.1, and 4.6 percent, respectively).

"Increasing thickness at highly cortical sites is an effective way to improve bone strength and mechanical integrity of the skeleton," Thomas Beck, of Johns Hopkins University in Baltimore, said in a statement. "These observations support the potential of targeting RANK Ligand to improve bone structural strength."

Other highlights included a series of Wyeth-supported studies demonstrating the efficacy of bazedoxifene, a selective estrogen receptor modulator. In one study, researchers presented results of a two-year extension of a three year Phase 3 trial in which 7,492 healthy postmenopausal women were randomly assigned to receive either daily treatments with 20 mg or 40 mg of bazedoxifene, 60 mg of raloxifene, or placebo. A total of 4,216 women were enrolled in the two-year extension.

After five years, the researchers found that women taking 20 mg of bazedoxifene and those transitioned from the 40 mg dose to the 20 mg dose had a significantly reduced incidence of new vertebral fractures (4.5 and 3.9 percent, respectively) compared to women taking placebo (6.8 percent), which corresponded to relative risk reductions of 35 and 40 percent, respectively. However, they also found that women taking bazedoxifene had a higher incidence of venous thromboembolic events than those taking placebo after five years, a finding that also was observed after three years.

"These new data are important in that they suggest the reduction in vertebral fracture risk with bazedoxifene seen at five years is comparable to that seen at three years," Stuart Silverman, M.D., Clinical Professor of Medicine at the University of California and Cedars-Sinai Medical Center in Los Angeles, and the study's lead investigator said in a statement.

Another series of studies assessed the efficacy and tolerability of the bisphosphonate ibandronate in the treatment of osteoporosis. In one study, University of California at San Francisco researchers conducted a pooled analysis of two long-term extension studies. Compared to placebo, they found that five years of treatment with ibandronate was associated with a sustained reduction in fracture rates, and that rates were similar among women receiving either intravenous or oral ibandronate (14.07 to 15.42 and 14.77 to 15.34 percent, respectively).

In a second study of more than 12,000 women prescribed once-monthly oral ibandronate, German researchers observed high rates of patient compliance, user satisfaction and tolerability (more than 90 percent after six and 12 months).

Researchers from both studies reported financial relationships with multiple pharmaceutical companies, including GlaxoSmithKine and Roche.

Other highlights included a celebration of the 40th anniversary of bisphosphonates. "We had a wonderful symposium featuring speakers from different countries discussing the history of bisphosphonates and the new generation of bisphosphonate and their application, not just in treating osteoporosis, but their beneficial effects in stopping bone resportion with cancer metastasis and how the biological and chemical action of these drugs on the cells can help to reduce tumor burden," Lian said.

One of the meeting's key themes was "Bone: The Center of the Endocrine Universe." "It reflects the broader scope of what's happened to the bone field," Lian said. "It's appreciated now how bone interfaces with so many other organ systems. For example, the brain is secreting factors that affect bone, and the bone cells are secreting factors that affect energy metabolism.

"One of the important discoveries of the past few years is that the hormones leptin and serotonin are regulating both bone mass and are controlling energy metabolism. That's a very exciting area, as exciting as the immune system T cells and B cells cross-talking with bone. Another exciting area is the ability of bone to hide stem cells that can be used to regenerate other tissues."

ASBMR: Treatments Improve Bone Health in Breast Cancer

WEDNESDAY, Sept. 16 (HealthDay News) -- Among breast cancer patients who receive adjunctive hormonal therapy with aromatase inhibitors, secondary causes of bone loss can be successfully treated, according to research presented this week at the annual meeting of the American Society for Bone and Mineral Research, held from Sept. 11 to 15 in Denver.